• Disconnected diagrams with twisted-mass fermions

      Abdel-Rehim, A; Alexandrou, C; Constantinou, M; Finkenrath, J; Hadjiyiannakou, K; Jansen, K; Kallidonis, C; Koutsou, G; Avilés-Casco, AV; Volmer, J (2016-01-01)
      © Copyright owned by the author(s). The latest results from the Twisted-Mass collaboration on disconnected diagrams at the physical value of the pion mass are presented. In particular, we focus on the sigma terms, the axial charges and the momentum fraction, all of them for the nucleon. A detailed error analysis for each observable follows, showing the strengths and weaknesses of the one-end trick. Alternatives are discussed.
    • Disconnected quark loop contributions to nucleon observables using N<inf>f</inf> = 2 twisted clover fermions at the physical value of the light quark mass

      Abdel-Rehim, A; Alexandrou, C; Constantinou, M; Hadjiyiannakou, K; Jansen, K; Kallidonis, C; Koutsou, G; Avilés-Casco, AV (2015-01-01)
      We compute the disconnected quark loops contributions entering the determination of nucleon observables, by using a Nf = 2 ensemble of twisted mass fermions with a clover term at a pION mass mπ = 133 MeV. We employ exact deflation and implement all calculations in GPUs, enabling us to achieve large statistics and a good signal.